Normal Body Temperature in Older Adults: No Age-Specific Difference

Normal body temperature range is 36.5–37.5°C (97.7–99.5°F) for all adults, including seniors. Age does not change the set point.

Important Nuances in Older Adults

• Blunted fever response: Impaired thermoregulation, reduced cytokine response, comorbidities, medications (beta-blockers, anticholinergics) → older adults may not mount a fever despite serious infection. Absence of fever does not rule out infection.
• Lower baseline: Some frail elders run slightly lower (36.0–36.5°C). Know the individual's baseline.
• Hypothermia risk: Increased due to reduced shivering, vasoconstriction, subcutaneous fat, cognitive/medication factors.

Measurement

• Oral, tympanic, temporal artery, rectal (gold standard). Axillary less accurate.
• Consistent site and time of day for trending.

Clinical Takeaway

In older adults, assess for infection based on functional change (confusion, falls, anorexia, lethargy, incontinence) rather than fever alone. Sepsis criteria (qSOFA, SIRS) apply regardless of temperature.